The mechanism of corrosion of dental amalgam restorations, and the effects of corrosion on the properties of dental amalgam of various compositions and structures will be studied in vitro. The rate of deterioration in various types of dental amalgam under controlled conditions of exposure will be determined metallographically and by microanalytical techniques, and the results will be correlated with electrochemical data. The occluded cell corrosion in restorations will be simulated in special cells and the electrochemical parameters and solution chemistry changes will be measured; the emphasis will be on the behavior of high-copper dental amalgam. The electrochemical properties of the silver-mercury(-tin) phase will be determined using samples with various concentrations of tin. An extensive study of the effects of general, galvanic, and crevice corrosion on the tensile, compressive, and creep properties of a wide variety of amalgam types will be made. BIBLIOGRAPHIC REFERENCE: M. Marek, R. F. Hochman and T. Okabe, "In vitro Corrosion of Dental Amalgam Phases," J. Biomed. Mater. Res., 10, 789-804 (1976).